* Refactored ACL for the backend
  * ACL resources
    * Strict configuration format, validated by XSD schema
    * ACL configuration relocation from `app/code/<pool>/<namespace>/<module>/etc/adminhtml.xml` to `app/code/<pool>/<namespace>/<module>/etc/adminhtml/acl.xml`
    * Renamed ACL resource identifiers according to the format `<namespace>_<module>::<resource>` throughout the system
      * Backend menu configuration requires to specify ACL resource identifier in the new format
      * Explicit declaration of ACL resources in `app/code/<pool>/<namespace>/<module>/etc/system.xml` instead of implicit relation by XPath
    * Migration tool `dev/tools/migration/acl.php` to convert ACL configuration from 1.x to 2.x
  * Declaration of ACL resource/role/rule loaders through the area configuration
    * Module `Mage_Backend` declares loader for ACL resources in backend area
    * Module `Mage_User` declares loaders for ACL roles and rules (relations between roles and resources) in backen...